Electrospun keratin-based nanofibers for biomedical and environmental applications

Electrospinning is a simple method to produce nanofibers with high specific surface. Keratin is a biocompatible and biodegradable protein extracted from wool, which can be electrospun pure or in blend with other polymers, such as polyamide. It supports fibroblasts and osteoblasts growth. Moreover, nanofiber-based filters can remove small-sized particles and keratin nanofibers can absorb heavy metals and dyes from water, and VOCs from air. In biomedical applications, pure keratin nanofibers was applied as bio-finishing to functionalize titanium surfaces of dental implants. The aim is the improvement of soft tissue adhesion avoiding epithelial down-growth and bacterial infiltration on the collar. Keratin nanofibers were found to greatly improve fibroblast cells growth already at 24h. In bone regeneration, nano-hydroxyapatite (HAp) was used in composite electrospun keratin-based nanofibers. Water was used as solvent to produce HAp/keratin-based composite nanofibers. The nanofibers have been tested for osteoblasts cells growth, showing biocompatibility by cell viability assay. Moreover, antibacterial keratin-based nanofibers were produced by the addition of a protein-complex containing Irgasan, as a model biocide. The material has a slow release with a very high antibacterial activity after 24 h. Air pollution and water contamination are severe environmental issues. The discharge of polluting wastewater harms the aquatic life, adversely affects human health and limits water resources. New water filtration systems based on electrospun nanofibers have been proposed. In addition, composite nanofibers embedding functional nanoparticles (i.e. TiO2, silver) allow the depuration of water from pollutant compounds and bacteria.